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Intraoperative cauterization of a 6-mm central area of the ectatic cornea inducing tissue whitening and shrinkage.
Source publication
This study aimed to evaluate the effect of intraoperative corneal cauterization on the postkeratoplasty refraction of patients with keratoconus.
A randomized clinical trial.
Thirty eyes of 29 patients with keratoconus undergoing standard penetrating keratoplasty by the same surgeon were evaluated (MB).
Standard penetrating keratoplasty included the...
Context in source publication
Context 1
... a central area, 6 mm in diameter, was outlined by means of a marker. Then, bipolar forceps were used to superficially cauterize this central area until whitening and shrinkage of corneal tissue were obtained (Fig 1). In all cases (with and without cauterization), a Barron suction trephine, 7.5 mm in diameter, was used to make a circular incision, which was deepened until the endothelium was perforated. ...
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Purpose:
To report long-term visual and astigmatism outcomes in cases of zig-zag femtosecond laser-enabled penetrating keratoplasty (FLEK).
Methods:
Retrospective review. Three hundred thirty-five eyes of 287 patients underwent (FLEK) with a zig-zag incision pattern. Patients were assessed preoperatively and underwent postoperative comprehensive...
Ipsilateral rotational penetrating autokeratoplasty technique may be an alternative to minimize the problem of long waiting lists for transplantation due to keratoconus.
To report the visual outcomes in keratoconus patients after ipsilateral rotational penetrating autokeratoplasty technique (IRPAK) associated with a crescent-shape resection of 0.5...
Aim:
To investigate the long-term results of penetrating keratoplasty (PK) in patients with keratoconus (KC) and to evaluate factors that might influence the final visual outcome.
Methods:
We retrospectively reviewed the data of all patients with clinical KC who had undergone PK by a single corneal surgeon in a single center from May 1980 to Dec...
Purpose:
To report 5-year results of microkeratome-assisted anterior lamellar keratoplasty (MK-ALK) in cases of keratoconus.
Methods:
Patients with advanced keratoconus and the thinnest corneal location 300 μ or more were recruited. A Carriazo-Barraquer microkeratome was used to remove a 200-μ cap from the recipient cornea, and to prepare a 300-...
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Address for correspondence: Fehim Esen, MD, FEBO. Istanbul Medeniyet Universitesi, Goztepe Egitim ve Arastırma Hastanesi, Goz
Hastalıkları Klinigi, Egitim Mahallesi, Dr. Erkin Caddesi, 34722 Kadıkoy, Istanbul, Turkey
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Citations
... Our findings revealed that in cases of advanced keratoconus, MTK performed before femtosecond-laser z-PK leads to significant improvement of UDVA and SRI at 6-months postoperative. Busin et al. previously reported that corneal cauterization performed prior to transplantation of the corneal graft resulted in a decrease of refractive error and astigmatism 11 . However, no corneal topography index measurements were performed in that study. ...
Microwave thermokeratoplasty (MTK) is a surgical procedure for the correction of pathologic corneal steepening. The purpose of this study was to examine the postoperative outcomes of eyes with advanced keratoconus that underwent femtosecond-laser zig-zag penetrating keratoplasty (z-PK) following MTK for reshaping of the central cornea. This study involved 32 eyes of 32 consecutive advanced keratoconus patients; i.e., 25 eyes of 25 patients who underwent MTK prior to z-PK (MTK + z-PK group), and 7 eyes of 7 patients who underwent z-PK alone (z-PK group). In all treated eyes, visual acuity (VA) and corneal topography were measured before surgery and at 6-months postoperative. At 6-months postoperative, the mean uncorrected distance VA (logarithm of the minimum angle of resolution) and surface regularity index (SRI) of the MTK + z-PK group was 0.62 ± 0.39 (mean ± standard deviation) and 1.26 ± 0.45, respectively, while that in the z-PK group was 1.02 ± 0.18 and 7.64 ± 3.22, respectively. Both variables were significantly better in the MTK + z-PK group than in the z-PK group ( P < 0.05). The findings in this study reveal that MTK prior to z-PKP is effective for improving UDVA and reducing the irregularity of corneal topography in patients with advanced keratoconus.
... 1 Factors identified that may contribute to post-DALK astigmatism include the centration of trephination of the recipient, 2 the thickness distribution in the donor button and its diameter, 3,4 and the suturing technique used. 5 Although better refractive outcomes after keratoplasty in eyes with corneas of a relatively regular shape have been described, 6 a correlation between preoperative and postoperative central keratometric astigmatism (KA) has not been identified. 7 However, the possibility that the preoperative peripheral corneal curvature may affect postoperative astigmatism has not been evaluated. ...
Purpose:
To evaluate the orientation of keratometric astigmatism (KA) after deep anterior lamellar keratoplasty (DALK) for keratoconus and its correlation with preoperative peripheral KA.
Methods:
This is a retrospective, single-center observational study including keratoconic patients undergoing DALK between January 2016 and January 2017 with regular astigmatism postoperatively. The orientation of postoperative KA was classified as with-the-rule (WTR), against-the-rule, or oblique and was correlated with the corresponding preoperative peripheral KA, calculated by the sinusoidal fitting of points of the axial keratometric power map at 8 mm diameter.
Results:
Forty-one keratoconic eyes were included, with the most common orientation of KA post-DALK being WTR (65.9%), followed by against-the-rule (19.5%) and oblique (14.6%). A significant correlation was found between preoperative peripheral KA and post-DALK KA regarding axis (P < 0.001, r = 0.88) and power (P = 0.0128, r = 0.23).
Conclusions:
The axis of post-DALK astigmatism and to a lesser extent its respective power in keratoconic eyes can be predicted using the preoperative peripheral KA, with "WTR" being the most common astigmatic orientation.
... Of the various surgical approaches available, [1][2][3][4] deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) are the procedures of choice for visual rehabilitation in advanced KC. 1,2 Though PK enjoys a high success rate for KC in terms of graft clarity and survival, 5-7 the post keratoplasty refractive results maybe unsatisfactory. [8][9][10][11][12][13] The aim of keratoplasty is to reduce the high corneal refractive power (and astigmatism) to one that can be successfully managed with glasses or contact lenses. Various authors have advocated the use of same size or 0.25 mm smaller donor trephine to reduce postoperative refractive errors as oversized donor trephines, 0.5 mm larger, tend to increase myopia. ...
Purpose
To compare axial length (AL) with vitreous cavity length (VCL) in patients with keratoconus and to ascertain whether graft size can be tailored to reduce myopic refractive error in patients with keratoconus undergoing penetrating keratoplasty (PK).
Patients and methods
The AL and VCL were measured prospectively in patients with keratoconus not undergoing PK (Group 1) and in normal phakic, emmetropic individuals (Group 2). A retrospective analysis of these measurements in patients with keratoconus who had undergone PK (Group 3) was also performed. The postoperative spherical equivalent (SE) was then correlated to size of donor buttons.
Results
Keratoconus patients tended to have a longer mean VCL than emmetropic normal individuals. The mean VCL of these patients (Group 1) was 16.49 mm±SD 1.13 compared to the mean VCL of 15.94 mm±SD 0.56 in normals (Group 2, P<0.0001). Patients with keratoconus who had an undersized graft showed reduced myopic refractive error compared to those with same size or oversized grafts.
Conclusion
VCL measurement is more accurate than AL measurement in deciding upon graft-host size disparity for corneal graft in patients with keratoconus. In patients with increased VCL, undersizing the donor button helps in reducing postoperative myopia. We recommend VCL measurement as part of the routine workup in all keratoconus patients undergoing corneal transplants.
... Bipolar cautery is typically used for this procedure. 9 Hot wire cautery can be used if the wire is red hot and does not actually contact the corneal surface. Otherwise, it may result in creation of surface irregularities and even perforation in thin, very ectatic corneas. ...
... A large number of studies have shown that PK surgery performed in keratoconic eyes usually leads to very satisfactory results in terms of VA, postoperative refractive error, and endothelial survival. [1][2][3][4][5][6][7] Most surgeons usually combine full-thickness removal of the central cornea (usually comprising an area 7.5 to 8.5 mm in diameter) with cone cauterization 6,25,26 or variations of the graft-host disparity, [25][26][27][28][29][30] with the purpose of collapsing the ectatic corneal dome and/or pulling the peripheral cornea towards the center. However, a variable number of keratoconus patients experience over time one or more endothelial rejection episodes, causing graft decompensation in up to 9% of eyes. ...
... A large number of studies have shown that PK surgery performed in keratoconic eyes usually leads to very satisfactory results in terms of VA, postoperative refractive error, and endothelial survival. [1][2][3][4][5][6][7] Most surgeons usually combine full-thickness removal of the central cornea (usually comprising an area 7.5 to 8.5 mm in diameter) with cone cauterization 6,25,26 or variations of the graft-host disparity, [25][26][27][28][29][30] with the purpose of collapsing the ectatic corneal dome and/or pulling the peripheral cornea towards the center. However, a variable number of keratoconus patients experience over time one or more endothelial rejection episodes, causing graft decompensation in up to 9% of eyes. ...
... Recently, to avoid this regression of effect, before performing the microkeratome cut we cauterized the central superficial cornea in 2 patients who were not part of this study. Similar to what we have experienced in PK patients, 6 cone cauterization has resulted in a final less myopic SE (within 1 D). ...
To evaluate the visual and refractive results of microkeratome-assisted lamellar keratoplasty (LK) performed on keratoconus patients intolerant to spectacles and contact lenses.
Prospective, noncomparative, interventional study.
A microkeratome-assisted LK procedure was performed on 50 eyes of 50 keratoconus patients. All patients were spectacle and contact lens intolerant.
All patients included in this study underwent a standard surgical procedure involving removal of a lamella (9 mm in diameter cut with the 250-microm microkeratome head) from the recipient cornea by means of a hand-driven microkeratome and suturing of a donor lamella (0.5 mm smaller in diameter than the removed corneal lamella, cut with the 350-microm microkeratome head) obtained from a cornea mounted on an artificial anterior chamber. Each patient was examined preoperatively and at different postoperative times (1 and 6 months and 1, 2, 3, and 4 years).
Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), 1-year best contact lens-corrected visual acuity (BCLCVA), refraction, and computerized analysis of corneal topography.
After suture removal was completed, both UCVA and best-corrected visual acuity were significantly improved over properative values at all examination times. One year postoperatively, when follow-up was still available for all patients, UCVA was better than 20/200 in 8 of 50 (16%) patients and BSCVA was > or =20/40 in 44 of 50 (88%) patients, whereas BCLCVA was > or =20/40 in all 50 patients. Refractive astigmatism within 4 diopters was seen in 43 of 50 (86%) patients. Corneal topographic patterns were classified as regularly astigmatic in 39 of 50 (78%) patients. The 1-year values did not change substantially at later postoperative examination times. Complications included preparation of donor grafts of poor quality that needed to be discarded (8 cases [16%]), irregular astigmatism of various degrees (11 cases [22%]), high-degree astigmatism requiring secondary intervention (6 cases [12%]), epithelial interface ingrowth (1 case [2%]), and cataract formation (1 case [2%]).
Microkeratome-assisted LK can be performed on corneas with moderate to advanced keratoconus with a minimal corneal thickness of >380 microm. The procedure is relatively simple, may be standardized in most of its parts, and does not involve time-consuming maneuvers. All complications recorded did not threaten vision and were dealt with successfully. Our results indicate that microkeratome-assisted LK is as efficacious as conventional penetrating keratoplasty for the surgical treatment of keratoconus. However, the time necessary to achieve stable results is considerably shorter.
... Currently, PKP results in moderate regular and irregular astigmatism, which is easily managed by various surgical techniques. 17,18 The complication rate (such as corticosteroid side effects and allograft reactions) has decreased during the last decade. 19 In the year 2000, Colin and associates 15 first published an article about their preliminary results regarding the management of keratoconus with Intacs. ...
To prospectively study the effects of the use of Intacs microthin prescription inserts for the management of keratoconus.
Prospective nonrandomized clinical trial.
Thirty-three eyes of 26 keratoconus patients (17 males and 9 females) ages 21 to 51 years (mean age, 32 +/- 9.7 years) were included in the current study. All patients had clear central corneas and contact lens intolerance. Patients were excluded if any of the following criteria applied after the preoperative examination: previous intraocular or corneal surgery; history of herpes keratitis; diagnosed autoimmune disease; and systemic connective tissue disease. Two Intacs segments of 0.45-mm thickness were inserted in the cornea of each eye, aiming at embracing the keratoconus area to try to achieve maximal flattening. Preoperative examination included uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), manifest refraction, keratometric data, and corneal topography.
Intacs were successfully implanted in all eyes. In one eye Intacs were removed after 3 months because of their improper (superficial) placement. The follow-up ranged from 1 to 24 months (mean: 11.3 months). The mean UCVA significantly improved from 0.13 +/- 0.14 (range, counting fingers [CF]-0.5) to 0.39 +/- 0.27 (range, CF-1.0) (P <.01). Of 33 eyes, 2 eyes lost 1 line of UCVA, and 3 eyes maintained the preoperative UCVA, whereas the rest (28 eyes) experienced a 1- to 10-line gain. The mean BCVA also improved from 0.47 +/- 0.31 (range, CF-1.0) to 0.64 +/- 0.26 (range, 0.1-1.0) (P <.01). Of 33 eyes, 4 eyes experienced 1- to 2-line loss of BCVA, 4 eyes maintained the preoperative BCVA, whereas the rest (25 eyes), experienced a 1- to 6-line gain. Of 3 patients (3 eyes) with unsatisfactory results, 1 patient improved with one segment removal and in 2 patients the segments were permanently removed. One of these eyes underwent successful PKP.
With mean follow-up of 11.3 months, intracorneal ring segments implantation improved UCVA and BCVA in the majority of the keratoconus patients. Even though the results are encouraging, concern still exists regarding the predictability as well as the long-term effect of such an approach for the management of keratoconus.
Purpose:
To investigate descriptions and inclusion criteria of keratoconus used in randomized trials assessing the efficacy of surgical and nonsurgical interventions.
Methods:
Systematic review: we searched (Pre-)Medline and the Cochrane Library from inception until December 2018 and checked the reference lists of included articles and reviews. We included randomized trials assessing the efficacy of any kind of keratoconus treatment. No language restrictions were imposed. We assessed articles against the inclusion criteria, extracted relevant data including any kind of keratoconus description, and examined the methodological quality.
Results:
Searches retrieved 459 nonduplicate records, and we included 57 randomized controlled trials investigating 9 different surgical interventions with the most used primary outcome measure being maximum keratometry. Only 15 (26.3%) described eligibility parameters regarding keratoconus staging/classification, of which 12 studies used the Amsler-Krumeich classification. Eleven studies were published before 1997 (before publication of the Consolidated Standards of Reporting Trials statement), and none of these described the use of a classification. From 1997 onward, 15 of 46 studies (32.6%) described the incorporation of a classification system (P = 0.051). The average methodological quality of included trails was modest.
Conclusions:
The evidence from randomized trials, even after introduction of the Consolidated Standards of Reporting Trials statement, remains ill-formed regarding a careful definition of keratoconus. This is unfortunate because imprecisions regarding the specification of included patients preclude clinicians to assess applicability, that is, the extent to which they can use inferences drawn from study participants regarding efficacy and adverse events in the care of individual patients.
Treatment of keratoconus has experienced great advances in the last two decades and a constant update is mandatory in order to offer these patients an adequate treatment. Nowadays, we have treatment options in order to halt the progression of the disease, and together with the advances in rigid gas permeable contact and scleral lenses fitting, and the possibility of minimizing the severity of the cone with technically easy and safe surgical procedures, it has been reduced the amount of patients that end up requiring a corneal transplant for their visual rehabilitation. However, we still observe cases with an advance disease at presentation as a consequence of a late diagnosis. In such cases corneal transplantation is still required so it is critical for the corneal specialist to master these techniques and to know how to deal with these patients along their postoperative period that will be extended for the rest of their lives. Lamellar transplant techniques opened a new hope for these patients and even today a lot of research is being done in order to simplify its techniques and to do them more reproducible for novel surgeons. In this chapter, we will review the different corneal transplant techniques available for keratoconus and the different technical modifications that we should take into account while managing this disease in order to enhance our patient’s surgical outcomes. We will review all the current evidence about the long-term results of these techniques and we will have a look to the future to discuss the new surgical options that may arrive in the next few years.
To review current techniques used in deep anterior lamellar keratoplasty (LKP), and to describe a novel approach that facilitates baring of Descemet's membrane (maximum depth anterior lamellar keratoplasty).
A highly selective review of the literature is presented, with descriptions of different techniques in the light of the authors' personal experience over 3 decades. A novel method for baring Descemet's membrane is detailed. It involves air injection in such a way that a large bubble is created between stroma and Descemet's membrane. Visual results of this operation in patients with keratoconus are reviewed.
Visual results 6 months after maximum depth anterior LKP in 181 eyes with keratoconus are comparable with those resulting from penetrating keratoplasty: 89% achieved a best spectacle-corrected visual acuity of 20/40 or better, and 10% achieved 20/20 or better. Intraoperative perforation occurred in 9% of cases.
Maximum depth anterior LKP has some important advantages when compared with other types of anterior lamellar keratoplasty or penetrating keratoplasty, but it remains a challenging procedure. A new technique considerably facilitates this operation and reduces intraoperative complications.
